fix safety issue in entries() iterator

Author: maltek

src/lib.rs

@@ -281,7 +281,6 @@ impl<K: Hash + Eq, V, S: BuildHasher> LinkedHashMap<K, V, S> {
         Entries {
             map: self,
             head: head,
-            tail: self.head,
             remaining: self.len(),
             marker: marker::PhantomData,
         }
@@ -844,7 +843,6 @@ pub struct IntoIter<K, V> {
 pub struct Entries<'a, K: 'a, V: 'a, S: 'a = hash_map::RandomState> {
     map: *mut LinkedHashMap<K, V, S>,
     head: *mut Node<K, V>,
-    tail: *mut Node<K, V>,
     remaining: usize,
     marker: marker::PhantomData<(&'a K, &'a mut V, &'a S)>,
 }
@@ -971,7 +969,7 @@ impl<'a, K, V, S: BuildHasher> Iterator for Entries<'a, K, V, S> {
     type Item = OccupiedEntry<'a, K, V, S>;
 
     fn next(&mut self) -> Option<OccupiedEntry<'a, K, V, S>> {
-        if self.head == self.tail {
+        if self.remaining == 0 {
             None
         } else {
             self.remaining -= 1;

tests/test.rs

@@ -140,6 +140,18 @@ fn test_entries_remove() {
 
     assert!(map.is_empty());
 }
+#[test]
+fn entries_insert() {
+    let mut map = LinkedHashMap::new();
+    map.insert(0, 0);
+    map.insert(1, 1);
+
+    let mut iter = map.entries();
+
+    iter.next().unwrap().insert(0);
+    iter.next().unwrap(); // 1
+    assert!(iter.next().is_none());
+}
 
 #[test]
 fn test_debug() {